CVE-2026-28973 Overview
CVE-2026-28973 is an integer overflow vulnerability [CWE-190] affecting multiple Apple operating systems. Apple addressed the issue with improved input validation across iOS, iPadOS, macOS, and watchOS. A malicious application exploiting this flaw may break out of its sandbox, gaining access to resources and capabilities normally isolated from third-party code. The vulnerability requires local access and user interaction, but the scope change component of the CVSS vector indicates it crosses trust boundaries when triggered. Apple published five coordinated security advisories covering the affected platforms.
Critical Impact
A malicious app installed on an affected Apple device may escape its sandbox and access data or system resources outside its permitted scope.
Affected Products
- Apple iOS (fixed in iOS 26.6) and iPadOS (fixed in iPadOS 26.6)
- Apple macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6
- Apple watchOS (fixed in watchOS 26.6)
Discovery Timeline
- 2026-07-27 - CVE-2026-28973 published to NVD
- 2026-07-28 - Last updated in NVD database
Technical Details for CVE-2026-28973
Vulnerability Analysis
CVE-2026-28973 is rooted in an integer overflow condition within an Apple operating system component shared across iOS, iPadOS, macOS, and watchOS. Integer overflows occur when an arithmetic operation produces a numeric value that exceeds the storage capacity of its data type, wrapping around to an unexpected value. When such a value is used to size a buffer, index memory, or gate a security check, the resulting mismatch can corrupt state or bypass validation logic.
Apple describes the fix as "improved input validation," indicating the vendor added bounds and sanity checks on the affected numeric input paths. Successful exploitation lets a malicious app break out of its sandbox, undermining the isolation model that constrains third-party applications on Apple platforms. The scope change in the vector reflects this crossing of the sandbox boundary.
The EPSS probability is 0.133%, suggesting a low near-term likelihood of broad opportunistic exploitation. However, sandbox escapes are commonly chained with other primitives in targeted attacks against mobile and desktop Apple devices.
Root Cause
The root cause is missing or insufficient validation of an integer input before it is used in a security-sensitive computation. When an attacker-controlled value drives arithmetic that overflows, downstream logic operates on a corrupted length or offset, enabling unintended memory or capability access.
Attack Vector
An attacker must deliver a malicious application to the target device and induce the user to run it. Once executing inside its sandbox, the app triggers the overflow to escape isolation. No network access or elevated privileges are required prior to exploitation.
No verified public proof-of-concept code is available. Refer to the Apple Security Advisory 128066 and the additional advisories for platform-specific details.
Detection Methods for CVE-2026-28973
Indicators of Compromise
- Unsigned, sideloaded, or newly installed applications spawning unexpected child processes or accessing files outside their container.
- Sandbox violation entries in system.log or unified logging referencing sandboxd, amfid, or unusual denials followed by privileged activity.
- Applications making system calls or IPC requests inconsistent with their declared entitlements.
Detection Strategies
- Monitor endpoints for Apple OS versions running below iOS 26.6, iPadOS 26.6, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6, or watchOS 26.6.
- Inspect Mobile Device Management (MDM) inventory for installed third-party applications with anomalous entitlements or recent installation timestamps.
- Correlate process telemetry to identify sandboxed apps executing binaries in privileged paths such as /usr/libexec or /System/Library.
Monitoring Recommendations
- Enable and forward unified logs from macOS endpoints to a centralized analytics platform to retain sandbox denial and entitlement events.
- Alert on new binaries executed by processes whose parent bundle identifier belongs to a third-party App Store or sideloaded app.
- Track OS version compliance continuously and prioritize non-compliant devices belonging to high-value users.
How to Mitigate CVE-2026-28973
Immediate Actions Required
- Update all affected devices to iOS 26.6, iPadOS 26.6, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6, or watchOS 26.6 as applicable.
- Enforce patch compliance through MDM policies and block network access for devices that remain on vulnerable versions.
- Audit installed third-party applications and remove any that are unnecessary, unsigned, or from untrusted sources.
Patch Information
Apple released fixes across five advisories: Apple Security Advisory 128066, Apple Security Advisory 128067, Apple Security Advisory 128068, Apple Security Advisory 128071, and Apple Security Advisory 128072. The fixed versions are iOS 26.6, iPadOS 26.6, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6, and watchOS 26.6.
Workarounds
- Restrict application installation to the official App Store and vetted MDM-managed catalogs until patching completes.
- Disable sideloading and developer mode on managed iOS and iPadOS devices via MDM configuration profiles.
- Apply the principle of least privilege by revoking unnecessary entitlements and configuration profiles from user-installed applications.
# Verify current OS build on macOS and confirm patched version
sw_vers
softwareupdate --list
softwareupdate --install --all --restart
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
